In order to analyze the impact of brainstem strokes at different sites on the control of respiration in human beings, we correlated MRT-located ischemic brainstem lesions with sleep-related breathing disorders, measured by whole-night polysomnography, and the hypercapnic ventilatory drive during wakefulness, using a steady-state test, in 18 patients (17 men, mean age: 57 yrs, range 44-72 yrs), suffering from medullary/cerebellar lesions (group M, n=5), isolated pontine lesions (group P, n=7) and combined lesions of the pons and other brain regions (group P+, n=6). Patients were examined 6.5 (median, IqR 5.8) weeks after the incident. The HCVR slopes significantly differed between P (1.9 ± 0.5 l/min/Torr) and P+ (0.7 ± 0.5 l/min/Torr, p<0.005, ANOVA), with M at 1.19 ± 0.7 l/min/Torr (n.s.). P tended to lower apnea-hypopnea indices (P: 7.6 ± 6.5 /h; P+: 23.3 ± 25.6 /h; M: 25.0 ± 19.5 /h; n.s.). We conclude that in contrast to isolated pontine lesions, combined pontine/midbrain lesions coincide with a reduced hypercapnic ventilatory response in patients suffering from brainstem strokes. Whether this is also true for medullary lesions has to be proven in a larger number of patients.